Wholly aromatic polyester resins have long been known. For instance, 4-hydroxybenzoic acid homopolymer and copolymers have been provided in the past and are commercially available. Such polymers commonly are crystalline in nature, relatively high melting or possess a decomposition temperature which is below the melting point, and when molten frequently exhibit an isotropic melt phase. Molding techniques such as compression molding or sintering may be utilized with such materials. Representative publications which discuss these wholly aromatic polyesters include: (a) Polyesters of Hydroxybenzoic Acids, by Russell Gilkey and John R. Caldwell, J. of Applied Polymer Sci., Vol. II, Pages 198 to 202 (1959), (b) Polyarylates (Polyesters From Aromatic Dicarboxylic Acids and Bisphenols), by G. Bier, Polymer, Vol. 15, Pages 527 to 535 (August 1974) (c) Aromatic Polyester Plastics, by S. G. Cottis, Modern Plastics, Pages 62 and 63 (July 1975), and (d) Poly(p-Oxybenzoyl Systems): Homopolymer for Coatings: Copolymers for Compression and Injection Molding, by Roger S. Storm and Steve G. Cottis, Coatings Plast. Preprint, Vol. 34, No. 1, Pages 194 to 197 (April 1974). See also, U.S. Pat. Nos. 3,039,994; 3,169,121; 3,321,437; 3,553,167; 3,637,595; 3,651,014; 3,662,052; 3,668,300; 3,723,388; 3,759,870; 3,767,621; 3,773,858; 3,787;370; 3,790,528; 3,829,406; 3,857,814; 3,884,876; 3,890,256; 3,974,250; and 3,975;487; and U.K. patent application No. 2,058,102A.
It has been disclosed that certain polyesters may be formed which exhibit melt anisotropy. See, for instance, (a) Polyester X7G-A Self Reinforced Thermoplastic, by W. J. Jackson, Jr., H. F. Kuhfuss, and T. F. Gray, Jr., 30th Anniversary Technical Conference, 1975 Reinforced Plastics Composites Institute, The Society of the Plastics Industry, Inc., Section 17-D, Pages 1-4; (b) Belgian Pat. Nos. 838,935 and 838,936, (c) Dutch Pat. No. 7505551; (d) West German Nos. 2520819, 2520820, 2722120, 2834535, 2834536 and 2834537; (e) Japanese Nos. 2132-116; 3017-692; 3021-293; and 53-36594; (f) U.S. Pat. Nos. 3,991,013; 3,991,014; 4,057,597; 4,066,620; 4,067,852; 4,075,262; 4,083,829; 4,093,595; 4,118,372; 4,130,545; 4,130,702; 4,146,702; 4,153,779; 4,156,070; 4,159,365; 4,161,470; 4,169,933; 4,181,792; 4,183,895; 4,184,996; 4,188,476; 4,201,856; 4,219,461; 4,224,433; 4,226,970; 4,230,817; 4,232,143; 4,232,144; 4,238,598; 4,238,599; 4,238,600; 4,242,496; 4,245,082; 4,245,084; 4,247,514; 4,256,624; 4,265,802; 4,267,304; 4,269,965; 4,272,625; 4,272,803; 4,285,852; 4,287,332; 4,294,955; 4,299,756; 4,314,073; 4,314,688; 4,318,841; 4,318,842; 4,332,759; 4,333,907; 4,335,232; 4,355,132; 4,337,191; 4,339,375; 4,347,349; 4,351,917; 4,351,918; 4,355,133; 4,359,569; and 4,360,658; and U.S. Ser. No. 395,372 filed July 6, 1982 (now U.S. Pat. No. 4,375,372); (g) U.K. Application No. 2,002,404; and (h) European Patent Application Nos. 24,499 and 45,499.
Representative disclosures of anisotropic melt forming polyesters, poly(ester-amides), or poly(ester-carbonates) which may include 6-oxy-2-naphthoyl moiety are present in U.S. Pat. Nos. 4,161,470; 4,219,461; 4,256,624; 4,279,803; 4,299,756; 4,318,841; 4,318,842; 4,330,457; 4,337,190; 4,347,349; 4,351,917; 4,351,918; 4,355,133; and 4,359,569; and commonly assigned U.S. Ser. Nos. 319,024, filed Nov. 6, 1981 (now U.S. Pat. No. 4,371,660); 401,932, filed July 26, 1982; and 402,882, filed July 29, 1982.
Representative disclosures of anisotropic melt forming polyesters or poly(ester-amides) which may include 2,6-dioxyanthraquinone moiety are present in U.S. Pat. Nos. 4,188,476; 4,224,433; 4,341,688; 4,355,134; and U.S. Ser. No. 319,521, filed Nov. 9, 1981 (now U.S. Pat. No. 4,395,307).
In U.S. Pat. No. 4,219,461 a polyester is disclosed which comprises substantial concentrations of 6-oxy-2-naphthoyl and 4-oxybenzoyl moieties, and symmetrical dioxyaryl and symmetrical dicarboxyaryl moieties.
In commonly assigned U.S. Ser. No. 401,932, filed July 26, 1982, a polyester is disclosed which comprises a lesser concentration 6-oxy-2-naphthoyl moiety, 4-oxybenzoyl moiety, a symmetrical dioxyaryl moiety, and a dicarboxyaryl moiety.
In U.S. Pat. No. 4,299,756 a polyester is disclosed which comprises 6-oxy-2-naphthoyl moiety, 3-phenyl-4-oxybenzoyl or 2-phenyl-4-oxybenzoyl moiety, 1,3-dioxyphenylene moiety, and terephthaloyl moiety.
In U.S. Pat. No. 4,318,841 a polyester is disclosed which comprises 6-oxy-2-naphthoyl moiety, 4-oxybenzoyl moiety, the non-symmetrical 1,3-dioxyphenylene moiety, and terephthaloyl moiety.
In commonly assigned U.S. Ser. No. 319,521, filed Nov. 9, 1982 (now U.S. Pat. No. 4,395,307), entitled "Thermotropic Liquid Crystal Polymer Pulp and Method of Preparation Thereof Wherein Said Polymer Comprises Recurring Units Which Contain a 2,6-Dioxyanthraquinone Moiety" is disclosed in Example 1 the formation of a pulp beginning with the polyester of the present invention. The present invention was made prior to the pulp formation invention of U.S. Ser. No. 319,521.
It is an object of the present invention to provide an improved wholly aromatic polyester which exhibits an optically anisotropic melt phase and an unusually low melting temperature.
It is an object of the present invention to provide an improved wholly aromatic polyester which is particularly suited for use as a matrix resin in the formation of a fiber reinforced composite article.
It is a further object of the present invention to provide an improved wholly aromatic polyester which alternatively may be melt extruded at an unusually low extrusion temperature to form fibers and films.
These and other objects, as well as the scope, nature and utilization of the invention will be apparent to those skilled in the art from the following detailed description.